Comparative genome features and secondary metabolite biosynthetic potential of Kutzneria chonburiensis and other species of the genus Kutzneria.

Actinobacteria are well known as a rich source of diversity of bioactive secondary metabolites. Kutzneria, a rare actinobacteria belonging to the family Pseudonocardiaceae has abundance of secondary metabolite biosynthetic gene clusters (BGCs) and is one of important source of natural products and worthy of priority investigation. Currently, Kutzneria chonburiensis SMC256 has been the latest type-strain of the genus and its genome sequence has not been reported yet.

Streptomyces antimicrobicus sp. nov., a novel clay soil-derived actinobacterium producing antimicrobials against drug-resistant bacteria.

A novel actinobacterium, designated strain SMC 277T, was isolated from the clay soil in paddy field of Chonburi Province, Thailand, and characterized using polyphasic taxonomy. Strain SMC 277T formed straight chains of nonmotile cylindrical spores with smooth surface developed on aerial mycelia. The typical chemotaxonomic properties of members of the genus Streptomyces were observed in strain SMC 277T, e.

sp. nov., isolated from mountain forest soil.

A novel actinomycete, strain SMC 257, was isolated from a soil sample collected from mountain forest, Nan Province, Thailand. Strain SMC 257 formed tightly closed spiral spore chains on aerial mycelia. A polyphasic approach was used for the taxonomic study of this strain.

Pseudonocardia mangrovi sp. nov., isolated from soil.

A novel Gram-stain-positive, aerobic actinomycete, designated strain SMC 195, was isolated from soil collected from a mangrove forest in Thailand. The strain produced extensively branched substrate and aerial mycelia. The substrate mycelium was fragmented into rod-shaped elements, and spore chains consisting of smooth and rod-shaped spores were formed on the aerial mycelium.

Kutzneria chonburiensis sp. nov., isolated from soil.

A novel actinomycete strain, SMC 256T, which developed small, globose sporangia at the ends of long sporangiophores on aerial mycelium, was isolated from soil collected in a mountain forest of Thailand. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain SMC 256T belonged to the genus Kutzneria, and the closest phylogenetically related species were Kutzneria buriramensis BCC 29373T (98.9 % 16S rRNA gene sequence similarity), Kutzneria kofuensis ATCC 27102T (98.

Formation of catalytically active cross-species heterodimers of thymidylate synthase from Plasmodium falciparum and Plasmodium vivax.

Thymidylate synthase (TS) of Plasmodium dihydrofolate reductase-thymidylate synthase (DHFR-TS) functions as a homodimeric enzyme with two active sites located near the subunit interface. The dimerization is essential for catalysis, since the active site of each subunit contains amino acid residues contributed from the other TS domain. In P.

Subunit complementation of thymidylate synthase in Plasmodium falciparum bifunctional dihydrofolate reductase-thymidylate synthase.

Thymidylate synthase of Plasmodium falciparum dihydrofolate reductase-thymidylate synthase (PfDHFR-TS) functions as a dimeric enzyme with extensive contact between the two TS domains. Structural data of PfDHFR-TS shows that the formation of the two TS active sites involves contribution of the amino acid residues from both TS domains. Arg-470 donated from the adjoining domain is shown to hydrogen-bond to dUMP, while Cys-490 is a key nucleophile for TS catalysis by attacking C-6 of dUMP.